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Analysis of stable isotopes in fish mucus during a controlled diet switch
Citation:
CHURCH, M., J. L. EBERSOLE, K. RENSMEYER, R. Couture, AND D. Noakes. Analysis of stable isotopes in fish mucus during a controlled diet switch. Presented at The 2010 Conference Oregon chapter American Fisheries Society, Eugene, OR, February 24 - 26, 2010.
Impact/Purpose:
We have used a controlled diet switch in steelhead trout (Oncorhynchus mykiss) at the Oregon Hatchery Research Center to study the time rates of changes in stable isotopes of carbon and nitrogen (13C and 15N) in epidermal mucus, a rapidly responding “tissue.”
Description:
We have used a controlled diet switch in steelhead trout (Oncorhynchus mykiss) at the Oregon Hatchery Research Center to study the time rates of changes in stable isotopes of carbon and nitrogen (13C and 15N) in epidermal mucus, a rapidly responding “tissue.” Because of the rapidity with which mucus responds, due to high rates of synthesis and turnover, it holds promise for stable isotope analyses of diet or habitat switching of fish in certain natural situations. Controlled diet switch studies of mucus dynamics in fish are very limited, however. In our experiment we switched the diets of eighteen individually PIT-tagged fish from one with relatively higher delta values (13C = -18, 15N = 15) to one with relatively lower delta values (13C = -24, 15N = 6). Delta values for actively feeding fish responded rapidly in mucus with half lives typically less than 20 days. Assuming that mucus is synthesized primarily from either recently ingested feed or recycled muscle tissue allows computation, via the reaction progress variable approach of Cerling et al., of the relative contribution of each source to mucus synthesis. To our knowledge, such determinations have not been previously reported.